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Connecting LM335Z temperature sensors to the P2 — Parallax Forums

Connecting LM335Z temperature sensors to the P2

These LM335Z temperature sensors are sometimes described as 'venerable' but they have the advantage of being relatively available

This code takes advantage of the 1mA pull-up current source built into every P2 smart pin, to power/bias the LM335Z sensor, which connects between the P2 I/O Pin and ground. No other components are necessary, unless you want to trim the zero (using a 10k trimpot). This is MicroPython code, but easy translates to other languages

In the plot window I've used finger pressure to heat the LM335Z, and a really short burst of cooling spray to go below the zero, then finger pressure to heat up again.

I'll post the LM334Z code soon, too. The LM334Z is nicer in that you can trim for 1.65v zero point, so you can use the 'zoom' ADC ranges of the P2
1920 x 1080 - 165K

Comments

  • Finally ordered my LM334Z so I can turn this into a P2 Quick Byte.

    Nom nom nom. All I think about is P2 Quick Bytes anymore.

    KG
  • Way to go. Get some LM335Z's as well for the whole enchilada...
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